(1) Field of the Invention
The present invention relates to a grinding machine, and more particularly, to a swing device for swing the sanding belt of a grinding machine.
(2) Description of the Prior Art
A conventional grinding machine for polishing surfaces of wood objects generally includes a sanding belt which is rotatably mounted to two mandrels and one of which is driven by a motor so as to grind the wood objects located beneath the lower mandrel. The sanding belt is rotated at high speed and can effectively polish the wood objects.
However, the sanding belt does not move parallel to the mandrels so that the objects are ground at the fixed portion of the sanding belt and this results in accumulation of debris on the grinding portion of the sanding belt and reduces the grinding efficiency. Besides, the objects could be burned due to the high speed grinding at the fixed portion of the sanding belt. Furthermore, the sanding belt needs to be replaced frequently because the sanding portion wears quickly.
The present invention intends to provide a swing device for changing the grinding portion of the sanding belt that is in contact with the objects so as to improve the drawbacks mentioned above.